The present invention relates to a casing having a watertight structure which is available for portable electronic apparatus or the like, which uses a battery requiring gas permeance, such as an air-zinc battery.
In a conventional casing of this type, a cup-shaped case houses therein electronic parts. A cover is attached to the case through a sealing member interposed therebetween so as to close an opening of the case, thereby defining a watertight casing. The sealing member prevents moisture contained in the atmosphere from penetrating into an interior of the casing.
The casing is encountered with a problem that it is impossible to incorporate therein a battery requiring gas permeance, e.g. an air-zinc battery since the casing is sealed to prevent permeance of air.